This invention relates to a fluid drain valve and particularly to an improved manually releasable drainport closure. The drainport closure according to this invention is particularly useful for implementation as a drain closure for a motor vehicle radiator to permit coolant draining therefrom.
Conventionally used drainport closures for motor vehicles comprise a screw type valve having a wing head for hand rotation and are often referred to as "petcocks." A hollow threaded member of a conventional petcock seats within an internally threaded metal socket. Upon rotation of the screw plug, fluid is permitted to drain through the interior of the plug. This configuration permits coolant which may be at an elevated temperature or a corrosive liquid to come in contact with the operator loosening the petcock. Conventional petcocks are prone to failure due to corrosion of the metal parts over time. Moreover, conventionally designed petcocks tend to be expensive due to the requirement of a number of metal machine parts. Often times a corroded petcock cannot be easily released thereby requiring the use of tools or cannot be removed without causing permanent damage to the components.
The improved manually releasable drainport closure according to this invention overcomes the above shortcomings of such valves according to the prior art. The drainport closure according to this invention is easily hand operated, is not subject to corrosion damage and is much less expensive to fabricate than those designs according to the prior art. Moreover, the drainport closure disclosed herein may be easily intentionally removed and yet is difficult to remove through inadvertence.